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多年冻土热状态和土壤季节冻融过程的变化对陆地生态系统、地-气间温室气体交换、水文和地貌过程以及工程基础设施的建设和运行都具有很大的影响。活动层和多年冻土及其变化数据信息对于验证在不同尺度的陆面过程、水文、生态和气候模型至关重要。本文就目前全球多年冻土与气候变化研究现状进行概括性总结。在全球变暖的影响下,全球范围内多年冻土发生了不同程度的退化。自20世纪70年代末以来,北极高纬度低温多年冻土温度升高可达3℃。由于受相变潜热的影响,在不连续多年冻土区相对较高温度的多年冻土温度增加幅度较小。受局地条件的影响,个别站点多年冻土温度几乎没有发生变化,甚至有降温的趋势。高纬度多年冻土南界向北移动,而中纬度高山地区多年冻土下界向高海拔移动,导致全球多年冻土面积减少。活动层厚度变化具有较强的区域差异,其深度增加范围从几厘米到1m多不等。新的融区在形成,融区厚度在增加且其范围在扩大。导致全球范围内多年冻土温度升高、活动层厚度增加以及融区的形成主要是受气温升高和积雪条件变化所致。未来多年冻土研究应包括不同时-空尺度上的长期监测和数值模拟、多年冻土变化与大气、水文、生态系统、碳循环以及地貌过程的相互作用等方面。
Changes in the thermal state of permafrost and soil freeze-thaw season have a significant impact on terrestrial ecosystem, ground-atmosphere greenhouse gas exchange, hydrology and geomorphology processes as well as the construction and operation of engineering infrastructure. Active and permafrost and its change data information are crucial to validate land-surface processes, hydrology, ecology and climate models at different scales. This article summarizes the present status of global permafrost and climate change research. Under the influence of global warming, the global permafrost has undergone some degree of degradation. Since the late 1970s, the temperature increase of Arctic high latitudes and low temperature permafrost can reach 3 ℃. Due to the influence of latent heat of phase transformation, the increase of temperature of permafrost at relatively higher temperature in discontinuous permafrost regions is smaller. Affected by the local conditions, the permafrost temperature at individual sites hardly changed and even tended to cool down. The high latitude southward permafrost moves to the north, while the mid-latitude high mountain ranges the lower permafrost to high altitudes, resulting in a reduction in the global permafrost area. Active layer thickness changes have strong regional differences, the depth of the increase range from a few centimeters to 1m range. The new financial district is forming, the thickness of the financial district is increasing and its scope is expanding. As a result, the temperature of permafrost around the world increased, the thickness of the active layer increased, and the formation of the melting zone was mainly caused by the temperature increase and the change of snow conditions. Future studies on permafrost should include long-term monitoring and numerical simulation on different time-space scales, changes in permafrost and the interaction of the atmosphere, hydrology, ecosystems, carbon cycle and topography.